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### SECTION D.2.2.3.2

NEVADA’S RESPONSE

(to U.S. Departmen t of Interior, Na tional Park Serv ice Comment Letter)

D-57D-582.2.3.2 Nevada’s Response

Introductio n

The focus of the NPS follow-up comm ents is the Reid Gardner Generating Station, particularly as related to the BART em ission lim it f o r SO 2 and the determination of the BART control technology f o r NO x . NDEP notes that the NPS concur s with the BART technology NDEP has identified for the three u n its at the T r acy Ge nerating Station and the two units at the F o rt Churchill Generating Station as expressed in their f o llow-up comment to Comm ent 7 (see Appendix C).

USEPA’s BART guidance states: “The visibilit y regulations define BART as follows: Best Available Retrofit Technolo g y (BA R T) m ean s an em ission limitation based on t h e degr ee of reduction achievable throu gh the applic ation of the b est sy stem of continuo us emission reduction for each pollutant which is emitted by . . . [a BART- e lig ible source]

. The em ission lim it ation must be established, on a case-by -case basi s, taking int o consi d eration the t echnology available, the costs of

co m p liance, the energy and no n-air qua lit y enviro nmental im pact of com p liance, any poll u ti on control equipment in use or in existence at the sour ce, the re m a ining useful life of the source, and the degree of im p r ovement in visibility whic h m a y reas onably be anticipated to result from the use of such technolo g y .” 2

The pream ble to the BA RT guidance indicates that states are free to determ ine the weight and significan ce to be ass i gn ed to each statuto r y facto r 3 and also su ggests th e BART determination process allows states to id entify a technology which does not pose unacceptable costs of

com p liance, energy and/or nonair quality environm ental im pa cts 4 . In addition, the guidance provides that the s t ates u s e average and increm ental co sts to d e term ine the reasonab l en ess of

com p liance costs 5

. NDEP identified the BART technologies and em issi ons lim its on a case-by-case basis through an analysis of the five statutory f actors consistent w ith EPA guidan ce. NDEP evaluated the cos t s o f

com p liance based on the average cos t , increm enta l cost and capital cost. We evaluated the degree of visibility im provem e nt using NV En ergy’s m odeling data, which we supplem ented with the expected em issions reductions since m odeled visibility im pacts are proportional to

em ission rates. NDEP c onsistently evaluated the cost and visibility da ta by looking at clear breaks in the cost effectiveness of th e BART co ntrols and resulting visibility im provem e nt or

em issions reductions. E x am ination of Table 1, Appe ndix C, of this SIP reveals these breaks in cost benefit, as do the least cos t envelopes pr esen ted as Figu re 1 in each o f the NDEP BART determ ination review reports in Appendix B.

2 4 0 C F R Part 5 1 Ap pe ndi x Y (I V) ( A )

3 70 FR p a g e 391 30

4 70 FR p a g e 391 30

5 40 CFR Par t 51 A p p e n d i x Y ( I V ) (D ) (4 ) (b)

D-59BART is only one of the tools available for states to utilize in a long-term strategy to m eet their 2018 reasonable progress goal. Nevada’s 2018 reasonable progress goal is better than the uniform rate of progress when evaluated with NDEP’s proposed BART e m ission lim i t s. NDEP deem s our determ ination of BART c ontrol technol ogies and em ission lim its as consistent with USEPA gui dance and the RHR.

NPS Follo w-Up Comments

The NPS fol l ow-up comm ents are reproduced belo w in italics with NDEP’s follow-up response in plain tex t

. Comm ent num b ers refer to the original FLM comm ents received du rin g the FLM review with the comm enter and p a ge num b er en closed in parenthesis. Only FLM comm ents with NPS f o llow-up com m e nts are lis ted below. See Appendix C for the com p lete set of FLM comments on the FLM consulta tion draft of the SIP.

COMMENT 6 (FS) NPS follow-up : The BART p r ogram is designed to set emission limits to protect and improve visibility, which is a transitory, short-term attribute. NDEP should facilitate the goals of the BART program by regulating short-term emissions of NO x , a pollutant tha t sig n ificantly im pairs visib ility in the

area.

NDEP follow-up response: Nevada has identified NO x em ission lim its based on 12-m ont h rolling averages. W e have chosen this tim e period based on our industry’s operatio nal experience with retrof its. NV Energy has installed rotating opposed fire ai r on one of its units at Reid-G ardner (unit 4) and confronted serious operational problem s , creating a high degree of vari ab ility in the o p erational characteristics of the unit. In order to ensure that industry is not out of compliance because of such issues, Nevada has chosen the 1 2 -m onth rolli ng average. It should b e noted th at because it is a ro lling average, the averag e is calculated each m onth and not sim p ly at the end of a full calendar year.

NDEP deems our BART em ission lim its do f acilita te the go a l s of the BART program. Exam ination of IMPROVE m onitor data representi ng Clas s I areas in the states adjacent to Nevada reveals that NO x contributes to visibility impairm ent, but at levels consider ably less th an other pollutants (see NDEP’s response to NGO Co mm ent 4 in section 2.2.4 below). Those Class I areas where NO x significantly im pairs visibility are clearly influenced by m obile sources (i.e., Zion and Craters of the Moon).

No changes were m a de to Nevada’s draf t RH SIP as a resu lt of this comm ent.

COMMENT 7 (NPS-FWS p.5) NPS follow-up : It appears that NDEP ha s based its BART determinations upo n three factors, capita l c o st

, cost per ton , and incrementa l cost p e r to n . NDEP cites the $8 million cap ital cost of ROF A +Rotamix at Reid Gardner Generating Sta tion (RGGS) as one example of a parameter it considered. This is the highest capital cost of any NO x control strategy accepted by NDEP. Use of this cap on capita l cost improperly excludes co ntrols that m a y be more effective on other bases (e.g., $/ton,

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